Frequency of Combined Deficiencies of Vitamin D and Holotranscobalamin in Cancer Patients.

Low serum levels of vitamin D are associated with a higher frequency of at least eleven different malignancies including breast, colon, and prostate cancer (Holick, M.F. Vitamin D: Millenium Perspective. Journal of Cellular Biochemistry. 2003. 88:296–307). Low levels of vitamin B12 were found to contribute to a 2.5–4.0 times greater likelihood of breast cancer in postmenopausal women (Wu, K. et al. Cancer Epidemiol. 1999. 8:209–17) and hematological and mucosal tissue is more sensitive to chemotherapy in the presence of insufficient levels of B12. Only vitamin B12 that is complexed to transcobalamin as holotranscobalamin (HTCII) is metabolically active. It has been suggested that decreased HTCII serum levels are involved in the failure to methylate DNA resulting in the activation of oncogenes that would normally be dormant (Herbert, V. Methyl Metabolism: Epigenetics, Genomics, Proteomics. 2002 FASEB Summer Research Conference. Snowmass Village, Colarado.).Our study investigated vitamin D, total B12 and HTCII levels in 70 cancer patients. Vitamin D was measured as serum 25 OH-D3 (Nichols Advantage assay) and serum B12 was measured as both total B12 and as the metabolically active HTCII (Immulite B12 assay followed by glass adsorption: Vu, T. et al., Am J. Heme42: 202–211 1993). Vitamin D insufficiency has been defined based on differing physiologic sequelae of insufficiency and varies between values less than 50–75 nMol/L. When vitamin D insufficiency is defined as serum level 300pg/mL) while 17 of 52 (34%) were found to be HTCII insufficient (normal >69 pg/mL). Of these 17 patients, 14 (84.4%) had normal total B12 levels. Low levels of vitamin D strongly correlated with low serum HTCII. All 12 HTCII deficient patients were vitamin D insufficient at the